Efficient collectors of tubular variety are disclosed in U.S. Pat. No. 3,952,724 and commonly owned, copending application Ser. No. 634,714 filed Nov. 24, 1975 (now U.S. Pat. No. 4,033,327), both setting forth inventions of Y. K. Pei in modern, advanced solar collector design. The prior collectors just referred to utilize, for the most part, a liquid media to absorb and transmit energy as heat collected on a tubular solar absorbing surface of a collector. The liquid is handled in a manifold for series flow distribution thereof into the interior chamber of a series of absorber tubes. To maintain the circuit leakproof, the collectors are sealed in the manifold and end pressure on the tube is provided in the structural support to bias the internal liquid pressure in the interior chamber of the absorber tube as arise at operating temperatures of the system. The collectors are constructed from glass tubing components and have an annular vacuum jacket between the outside tube wall and the inside, absorber tube wall. The liquid is freely introduced from the manifold into the absorber tube interior by a delivery tube circuit from which the liquid flows within the confines of the absorber tube body to the manifold. Breakage of the tubular collector, and in particular, breakage of the absorber tube; or unseating and leakage of one of the collector tubes from the manifold causes leakage or spillage of liquid and a resulting malfunction, or, at best, loss of efficient operation of one module segment of the system.